The NFL collective bargaining agreement runs through 2021, meaning we are guaranteed four more years of labor peace. That doesn’t mean the two sides aren’t already preparing for war.

Speaking this week to MMQB’s Albert Breer, NFL Players Association Executive Director DeMaurice Smith said everyone — team owners, players, fans — should expect the league to grind to a halt when the CBA expires.

“I think that the likelihood of either a strike or a lockout in 2021 is almost a virtual certainty,” he said, before running through the NFL’s recent labor history.

“I don’t know now, but let’s look at our history,” Smith said. “The owners do a deal in 2006 and opt out in 2008. We do a deal in 2011 with no opt outs because we like the benefits under the current deal and we didn’t want to give the owners a chance to opt out and take back the gains that we currently have … So we have a new deal where if it doesn’t get fixed you head into a certain small-A armageddon.”

Smith has rattled his saber before. In January, after NFL Commissioner Roger Goodell and the team owners expressed an interest in extending the current deal, Smith said that wasn’t going to happen without significant changes to the CBA.

“There’s not gonna be an extension of the CBA,” Smith told The Post’s Mark Maske. “I don’t know what he’s thinking when he says extension. But there’s not gonna be an extension of the CBA. If the owners are interested in talking about issues that are currently covered by the CBA or issues that aren’t currently covered by the CBA and they want to have a renegotiation on some of those issues, we’ll have a renegotiation of those issues. But there’s not going to be a 2025 [or] 2027 addendum to the CBA that says, ‘We’re good with this.’

“I don’t think that’s what he meant when he said extension. But I don’t spend a whole heck of a lot of time trying to unpack what other people are thinking when they say stuff.”

A big sticking point will be the powers given to Goodell as commissioner. After the Deflategate brouhaha and the current war of words over Ezekiel Elliott, the union would prefer that an independent arbitrator decide player-conduct matters instead of Goodell, who has nearly unchecked authority to punish players as he sees fit. The two sides nearly agreed to amend the CBA to strip Goodell of those powers, but it all fell apart.

“The CBA evolves all the time,” Smith told Maske. “The best example is drug policy. So, I think it was a year and a half, two years ago the players thought — we thought — that we had an agreement, a stand-alone agreement on commissioner discipline that included neutral arbitration by a mutually selected group of judges. And at the last minute, they made the decision that they didn’t want to do a stand-alone agreement, that they wanted to do it as a part of something else, no. So if they want to talk about a renegotiation of important issues — and obviously commissioner discipline will come up — either it will get done or it won’t.”

As PFT’s Mike Florio points out, the NFL’s owners are seemingly happy with the status quo and could be willing to lock out the players or let them strike, with the assumption that few of them truly want to actually start missing game checks. That could change if the NFLPA girds them for labor war by warning those players who still plan to be playing in 2021 to start saving their money. In any case, what’s shaping up to be a protracted, messy battle is only beginning.

Matt BonesteelMatt Bonesteel spent the first 17 years of his Washington Post career writing and editing. In 2014, Bonesteel pivoted from the newspaper to online and now he blogs for the Early Lead and other Web-based products owned by The Post. Follow